Vert Photos display Larger than Horizontal

Christine: all I can say about your Water Lily theme is Excellent, Excellent, Excellent!!! I have a question on the display of my horizontal (320 x 190) & vertical (190 x 320) photos. Both orientations have same dimensions but vertical photos display bigger than the horizontal photos. Is there a way to fix this automatically? I suspect it has something to do with container dimensions that’s making the vertical photos appear larger. Here is my website: http://www.galleryviews.com/wordpress

Thanks,
Vic